55 Cancri Ae

55 Cancri Ae (abbreviated 55 Cnc Ae), officially named Janssen (, is a superterran exoplanet made almost entirely of carbon, likely in the form of diamond, giving it the nickname the diamond planet or Lucy (from the Beatles song Lucy in the sky with diamonds).  The planet orbits a sun like star just 2,400,000 kilometres from the star on average, pushing surface temperatures to an average of 2,575°K. The gravity of 55 Cancri e is around 15 times that of Earth, and the planet is tidally locked. The likelihood of diamonds on 55 Cancri e is due to the insane pressures on the planet. 55 Cancri E is also known of being up to double the size of Earth.

Name
In July 2014, the International Astronomical Union (IAU) started a contest called NameExoWorlds to give proper names to certain exoplanets (planets outside our solar system) and their host stars.NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars . IAU.org. 9 July 2014 People could suggest and vote on the names.

In December 2015, the IAU announced the winning name for this planet was Janssen.Final Results of NameExoWorlds Public Vote Released , International Astronomical Union, 15 December 2015. The name was submitted by the Royal Netherlands Association for Meteorology and Astronomy from the Netherlands. It honors the lens maker Zacharias Janssen, who some believe invented the telescope.

Orbit and rotation
55 Cancri e orbits its parent star very closely; so it only takes 18 hours to complete one trip around the star. 55 Cancri e might also share the same orbital plane (be coplanar) as the next planet in the system, 55 Cancri b. 

Because the planet is old and so close to its star, it is very likely to be tidally locked. This means that one side, called the dayside, constantly faces the star, while the other side, the nightside, always faces away.

References

Category:Exoplanets